DPT vaccine provides protection against:
DPT vaccine, also known as triple antigen, provides simultaneous protection against diphtheria, pertussis, tetanus three bacterial diseases responsible for high childhood morbidity mortality before immunization era. Diphtheria caused by Corynebacterium diphtheriae toxigenic strains producing diphtheria toxin transported to heart causing myocarditis, nerves neuritis and kidney necrosis plus pseudomembrane airway obstruction. Pertussis caused by Bordetella pertussis Gram-negative coccobacillus attaching ciliated epithelium via filamentous hemagglutinin, producing pertussis toxin ADP-ribosylating Gi proteins disrupting signaling causing lymphocytosis and paroxysmal cough apnea in infants. Tetanus caused by Clostridium tetani anaerobic spore forming bacterium in soil, producing tetanospasmin blocking glycine release causing spastic paralysis and respiratory failure mortality 80 percent without ICU. DPT contains diphtheria toxoid, tetanus toxoid, whole-cell killed pertussis wP or purified acellular aP antigens adsorbed. Simultaneous administration induces antitoxin antibodies neutralizing diphtheria and tetanus toxins and antibacterial antibodies against Bordetella preventing colonization. Schedule 6,10,14 weeks plus boosters ensures protection persisting into childhood, boosters DTaP at 15-18 months and Tdap adolescence due to waning pertussis immunity.
Ref: CDC Pink Book Diphtheria Pertussis Tetanus DPT; WHO DPT definition combined; Plotkin.